Medullobalstona Flashcards
(25 cards)
Medulloblasfoma is the
Prototype posterior fossa malignancy and 20% of all childhood brain tumors
It is a type of _____ and arises from
PNET and cerebellar stem cells
Histologic appearance
Small round blue cell
Tumor usually arises in
Midline of cerebellum and projects into fourth ventricle and brain stem
Have an inherent tendency to
Metastasize via cerebrospinal pathways
Approx how many patients present with CSF seeding
30-35%
Which has the greatest propensity for dissementstion through CSF
Anaplastic Medulloblasfoma
Presenting symptom occur over
Period of weeks or few months
Several symptoms can occur as a result of
Invasion and compression of fourth ventricle
Symbomps
Hydrocephalus
Morning vomit
Headaches
Ataxia
Cranial nerve abnormalities
CT and MRi usually shows
Round, central cerebellar, enhancing mass and hydrocephalus
Therapy is now based on tumor of greater than
1.5 cm and the extent of CSF or gross neural axis mets
Medullo blasting is one CNs tumor that can
Develop extra cranial masses, usually in bone
What is vital for good outcome s
Maximum resection
Surgery alone
Is rarely curative, maximum resection can lead to higher risk of complications such as posterior fossa syndrome
What staging system do they use
Chang system
Change systme
Size
Invasion of fourth ventricle and brain stem
Amount of CSF spread
The most common RT technique is
Lateral opposed fields for the brain and intracranial CSF spaces.
Careful
Shielding must be designed for
Anterior globe, pharynx, neck
Treatment couch is angled
A few degrees to compensate for divergence of the beam inferiorily into the spinal cord
The collimaotr is angled
On the brain fields to match divergaej of superior margin of the postant field
Depending on height
One or two posterior fields are used to encompass the spine down to the level of S2/S3
These children should be immobilized
In a prone position
Chin extended
